Mixing particulates or powders can be more difficult than mixing liquids. This can be apparent when one desires to precisely and accurately mix a known volume or mass of material. While a number of industrial processes and devices are directed towards powder mixing, these processes and devices have several disadvantages.
For example, a common method of mixing two or more powders involves combining the powders in an enclosed volume, such as a bag, and shaking or vigorously agitating the enclosed volume to mix the powders together. However, such a process achieves very limited results, and the resulting mixed powder remains relatively heterogeneous. Such methods are unsuitable for some situations, such as where small doses of a drug are to be delivered such that more reliable methods of mixing is required if there is to be any certainty in the amount of drug that is delivered.